A template for rigid stereotaxic afterloading brachytherapy of the brain

This paper describes a system for the implantation of rigid stainless steel afterloading tubes into the brain using a stereotaxic head frame for both localization and treatment.

The stereotaxic frame is attached to the skull throughout the treatment, and the afterloading tubes are both rigid and fixed to the frame. The source positions are therefore fixed relative to the skull throughout the irradiation. Design and construction of templates, afterloading tubes and clamps are discussed in detail.

The rigidity of the resulting implant provides accurate and immobile positioning of the planned isodose distribution relative to the defined treatment volume and makes it possible to carefully and rapidly plan a source loading which will best cover the volume of interest. The source template is not in contact with the patient at any time. The afterloading tubes are held strictly parallel during treatment, allowing for rapid and versatile preplanning prior to surgical placement. Placement options are enhanced by using a set of rotating templates.

This system has been used for over 60 procedures without any mechanical or safety problems and has provided a significant improvement in both the speed and confidence of localization and treatment planning. There are significant advantages of such a system for High Dose Rate Afterloading Brachytherapy.